dotnet run error Assert failure(PID 28188 [0x00006e1c], Thread: 26664 [0x6828]) in .net 9

[mammadkoma]

Description

I create a web api .net 9 project, it builds but after running dotnet run command it shows error. I don't have any problem in .net 8 on Windows 10.
The commands in .net 9 :
PS D:\TestProjects\WebApi> dotnet build
Restore complete (0.2s)
WebApi succeeded (2.4s) → bin\Debug\net9.0\WebApi.dll

Build succeeded in 3.0s
PS D:\TestProjects\WebApi> dotnet run
Using launch settings from D:\TestProjects\WebApi\Properties\launchSettings.json...
Building...
CLR: Assert failure(PID 28188 [0x00006e1c], Thread: 26664 [0x6828]): !AreShadowStacksEnabled() || UseSpecialUserModeApc()
File: D:\a_work\1\s\src\coreclr\vm\threads.cpp:7938 Image:
D:\TestProjects\WebApi\bin\Debug\net9.0\WebApi.exe
PS D:\TestProjects\WebApi>

Reproduction Steps

create a web api in .net 9

Expected behavior

running the project

Actual behavior

getting error

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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[mangod9]

@mammadkoma this looks related to CET. Are you able to reproduce the failure on different machines? Can you try to disable CET and check if the problem persists: https://learn.microsoft.com/en-us/dotnet/core/compatibility/interop/9.0/cet-support

[mammadkoma]

It runs after adding this line to the .csproj file :
<CETCompat>false</CETCompat>

So why should I add this line for .net 9 ?

[mangod9]

are you able to share a repro? Is this a simple webapi project created with dotnet new webapi ?

[mammadkoma]

Yes I created by dotnet new webapi command. It has this problem in other project types for example blazor webapp.

[JustArchi]

Also got user of my OSS app running into the same issue: JustArchiNET/ArchiSteamFarm#3348

Can't provide much more details on their environment, but the app definitely doesn't start now after .NET 9 upgrade.

CLR: Assert failure(PID 10336 [0x00002860], Thread: 9268 [0x2434]): !AreShadowStacksEnabled() || UseSpecialUserModeApc()
File: D:\a_work\1\s\src\coreclr\vm\threads.cpp:7938 Image:
D:\program\ASF-win-x64\ArchiSteamFarm.exe

[mangod9]

@janvorli FYI. Can they provide details on the hardware they are running on. Also weird that the assert is showing up here. Any repro and/or dumps if available would be helpful to diagnose.

So why should I add this line for .net 9 ?

in .NET 9 CET compat-mode is enabled by default, so if the hardware is capable CET would be enabled. It appears there are specific cases where it isnt quite working right.

[janvorli]

This means that the Windows are out of date quite a lot and so they don't contain the fix for a bug in the kernel that prevents .NET to work with CET enabled. I believe the fix was released about a year ago.

[mangod9]

Can we possibly report a better error here? Not sure how the assert shows up on release builds?

[MichalPetryka]

Can we possibly report a better error here? Not sure how the assert shows up on release builds?

runtime/src/coreclr/vm/threads.cpp

Line 7833 in 342936c

_ASSERTE_ALL_BUILDS(!AreShadowStacksEnabled() || UseSpecialUserModeApc());

It's a release assert.

[janvorli]

Can we possibly report a better error here?

We can replace that assert by a check and failfast with a message that will make more sense.

[mangod9]

yeah a better error with some details on required windows versions would be good for better clarity.